Methods for delivery of optical signals to tissue for the treatment of a disease or condition

ABSTRACT

Embodiments described herein provide methods for treating various conditions and diseases using an optical signal. In one or more embodiments an apparatus is providing having an optical window, which is used to deliver an optical signal to provide stimulation to one or more tissue sites in the body such as the brain, optic nerve, eye, ganglia, spine, or other like site. The optical signals can be used to treat a variety of neurological diseases and conditions including epilepsy, migraine headaches and chronic pain. In particular applications the optical signals can be used to treat, inhibit or prevent epileptic or other neurological seizures by providing an optical input to a foci or surrounding tissue in the brain causing the seizure. The optical signal may also be combined with an electrical signal to produce an aggregate effect in tissue for treating the disease or condition such as a neurological disease or condition.

RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.13/710,407, filed Dec. 10, 2012, which is a continuation of U.S. patentapplication Ser. No. 12/265,690 filed Nov. 5, 2008 (now U.S. Pat. No.8,332,037 issued Dec. 11, 2012), entitled “HOUSING STRUCTURE FOR AMEDICAL IMPLANT INCLUDING A MONOLITHIC SUBSTRATE”; the aforementionedapplications being hereby incorporated by reference herein in theirentirety for all purposes.

FIELD OF THE INVENTION

Embodiments described herein relate to housing structures for medicalimplants. More specifically, embodiments described herein relate tohousing and lid structures for hermitically sealed medical implants suchas pacemaker housings.

BACKGROUND

Medical implants are being used with increasing frequency to treat avariety of conditions from heart disease, to chronic pain andParkinson's disease. A number of these implants include electroniccircuitry for providing a pacing signal or other electrical stimulationof body tissue and/or monitoring a physiological function such as heartrate. Typically, the electronic circuitry for these devices is containedin a hermetically sealed housing to protect the circuitry from exposureto fluids and humidity present within the environment of the body. Thiscircuitry is coupled to one or more pacing or other leads which arecoupled to a connector (known as a header for pacemaker applications)that sits typically on the top portion of the housing. The headerincludes wiring that must be passed through the top the housing whilestill maintaining the hermetic seal. This may require one or more glassto metal or other labor intensive seals which are difficult and costlyto manufacture. Wires that pass through the housing often must bereconnected to a flex circuit or other internal connecter coupling thewires to the internal circuitry. This internal connector takes up spacein the housing making the housing larger. This can be less thandesirable since in many applications, the housing is desirablyfabricated as small as possible to so as to be implanted in anunobtrusive manner in pockets of fatty tissue in the patient's chest orabdomen. Additional constraints on available space within the housingcan result from the fact that since the housing is often made of aconductive metal, no circuitry can be placed on the housing. Thus, thereis a need for a housing cover or lid for pacemaker and other medicalimplants which allows for low cost electrical seals for pass throughwiring and electrical connections and increases the amount of availablespace within the housing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a lid structure including an antenna accordingto an embodiment of the invention.

FIG. 2 is a side view of the embodiment of FIG. 1.

FIG. 3a is a perspective/schematic view showing the construction of atypical pacemaker.

FIG. 3b illustrates the connection of a pacemaker to the heart.

FIG. 4 is a perspective view of an embodiment of the lid structure whichcan coupled to a pace maker housing.

FIG. 5a is a perspective view illustrating the placement of the lidstructure on a pace maker housing.

FIG. 5b is a perspective view illustrating the placement of the lidstructure at angle on the pace maker housing.

FIG. 6 is a perspective view illustrating the engagement of the lidstructure with a header connector.

FIG. 7a is a perspective view illustrating an embodiment of a housingbody for a pacemaker or other medical implant housing including anopening sized for placement of a monolithic substrate (with or without aframe).

FIG. 7b is a perspective view illustrating an embodiment of a monolithicsubstrate joined to the housing body of FIG. 7a so as to form anintegral structure.

FIG. 7c is a perspective view illustrating an embodiment of a medicalimplant housing including multiple monolithic substrate sections joinedto the housing.

FIG. 7d is a perspective view illustrating an embodiment of a medicalimplant housing including multiple monolithic substrate sections withconductive pins.

FIG. 7e is a side view illustrating another embodiment of a substratefor attachment to a medical implant housing, with this embodimentincluding an attached battery.

FIG. 7f is a perspective view illustrating an embodiment of an opticallytransparent substrate section joined to a housing body.

FIG. 7g is a side view illustrating placement and use of an emitter anddetector with an optically transparent substrate for in vivo sensingfrom the within a medical implant housing.

FIG. 7h is a side view illustrating use of an optically transparentsubstrate as an optical coupling for optical communication between theinterior and exterior of a medical implant housing.

FIG. 7i is a block diagram illustrating use of physiological data sensedthrough an optically transparent substrate as an input to modulate apacing signal.

FIG. 7j is a side view illustrating use of optical signals sent throughand optically transparent substrate to stimulate and/or treat a tissuesite.

FIG. 8a is top view of the lid structure illustrating use of conductiveportions to fabricate one or more electrical components including acapacitor and an inductor.

FIG. 8b is top view of the lid structure illustrating use of conductiveportions to fabricate one or more electrical components including acapacitor and a resistor.

FIG. 8c is a schematic view of the lid structure illustrating use ofconductive portions to fabricate an LC circuit.

FIG. 9a is a cross sectional view illustrating an embodiment of acapacitor constructed by fabricating conductive portions on oppositesurfaces of the substrate.

FIG. 9b is a cross sectional view illustrating an embodiment of acapacitor constructed by fabricating conductive portions within theinterior of the substrate.

FIG. 9c is a cross sectional view illustrating an embodiment of acapacitor constructed by fabricating a first conductive portion on thesurface of the substrate and a second conductive portion within theinterior of the substrate.

FIGS. 10a-10e illustrate various layers of an embodiment of a multilayermonolithic substrate having various components on each layer. FIG. 10ais a top view illustrating a top substrate layer, including an antenna.FIG. 10b is a top view illustrates an interior layer having a firstcapacitor plate. FIG. 10c is a top view illustrating another interiorlayer having a second capacitor plate. FIG. 10d is a top viewillustrating a bottom layer including an inductor, a connectorarchitecture for an attached device and an attached device. FIG. 10e isa cross sectional view of the multilayer substrate illustrating stackedsubstrate layers as well as attached components and devices.

FIG. 11a is a block diagram illustrating some of the typical circuitryon a pacemaker or other implantable pacing or stimulating device.

FIG. 11b is a schematic view of the lid structure illustratingintegration of circuitry fabricated on the substrate with circuitry ofthe medical implant.

FIG. 12 is a perspective view illustrating use of the antenna tocommunicate between a medical implant and an external communicationdevice.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments described herein provide lid and housing structures forvarious medical electronic implants housings including cardiac implantssuch as pacemakers, gastric implants, spinal implants and neuralimplants. Many embodiments include a lid or other cover structure thatallows one or more electrical components to be fabricated on a surfaceor interior of the lid structure so as to improve the utilization ofspace within the housing available for electronic circuitry and reducethe number of separately assembled electronic components. Variousembodiments also provide a lid structure including a plurality of viaswith connecting pins projecting through and hermetically sealed to thevias to reduce manufacturing cost and time of making hermetically sealedpass through electrical connections to electronic circuitry in thehousing.

In one embodiment, the invention provides a lid structure for a medicalimplant housing comprising a monolithic substrate comprising adielectric material, a conductive portion fabricated on at least one ofthe top or bottom surfaces or an interior of the substrate, a frame atleast partially surrounding a perimeter of the substrate, an antennapositioned on a top surface of the substrate, a plurality of viasprojecting at least partially through the substrate, a plurality ofconductive pins with at least one of the conductive pins projectingthrough a via. The pins which typically comprise a conductive metal suchas platinum or a platinum iridium alloy, are desirably configured toengage electrical connectors contained in a separate connectingstructure which sits atop the housing. The frame which typicallycomprises titanium or other biologically inert metal, is hermeticallyjoined to the substrate using brazing, such as gold brazing, or otherjoining method. It is also configured to be hermetically joined to theimplant housing by brazing or other joining method.

In various pacemaker applications, the lid structure can be configuredto be hermetically sealed to the pacemaker housing or container (knownas a can). In these and related embodiments, this can be facilitated bythe frame including a lip or flange which engages the pacemaker and cansubsequently be hermetically sealed to the can by brazing or otherjoining method. Additionally, in various pacemaker applications, the lidstructure including the pins, can be configured to be coupled to thepacemaker header or other related connector structure which sits atopthe pacemaker. The pins are desirably configured to engage or otherwisebe coupled to one or more female connectors in the header which areconnected to the pacemaker leads. Alternatively, the pins can bedirectly coupled to the lead connectors.

In another embodiment, instead of forming part of a lid structure thatis in turn joined to the housing, the substrate can be directly andhermetically joined to the housing so that the substrate is integral tothe housing and forms part of the housing wall. In these and relatedembodiments, the substrate can be hermetically joined to a frame whichis then hermetically joined a housing body which includes an openingthat is shaped to receive the frame. Alternatively, the substrate can bedirectly joined to the shaped opening.

The substrate typically comprises one or more dielectric materials knownin the art such as various dielectric ceramics. In some embodiments, thesubstrate can be fabricated from a substantially optically transparentmaterial such as glass or one or more optically transparent dielectricpolymers. Use of optically transparent materials for the substrateallows for the creation of an optical window in the substrate which canbe used as an optical conduit or coupling for optical sensing ofphysiologic data (e.g., oxygen saturation), sending and receivingsignals for optical communication and for delivering an opticalstimulation or pacing signal to a desired tissue site. Embodimentsemploying optical communication can be used to communicate various datafrom the pacemaker (or other device) to an external communication deviceas well as for reprogramming the pacemaker.

In various embodiments of a method of using a pacemaker (or otherstimulating device) housing having an optical window, the window can beused to sense physiologic data which is then used as input to modulatethe pacing signal generated by the pacemaker. This input can besupplemental to input received from the pacemaker leads or dependingupon the sensed data (e.g., a sudden decrease in blood pressure or PO₂levels), can actually become the primary input or otherwise over ridedata input from the leads. Various control algorithms can be employed toassign a weighting to the optical data input relative to the lead inputand determine what conditions will initiate an override. In anotherembodiment, the optical window can be used to deliver an opticalstimulating signal to a tissue site such as the brain. This signal canbe delivered along with an electrical signal also generated bystimulating device or another device. The two signals can besynchronized to produce an aggregate effect.

In one embodiment, a physiological function is paced by (i) providing orpositioning a pace maker apparatus to pace the physiological function,the pace maker including a housing having an optical window, theapparatus configured to generate a pacing signal; and (ii) opticallysensing physiologic data through the optical window; and modulating thepacing signal in response to the sensed physiologic data.

In still another embodiment, a biological tissue is stimulated by (i)providing or positioning a stimulator apparatus to operate in or on thebiological tissue, the stimulator apparatus including a housing havingan optical window, the apparatus configured to generate a stimulationsignal; and (ii) delivering an optical stimulation signal to tissuethrough the optical window.

The conductive portion will typically comprise a conductive metal suchas copper, gold, platinum or like metal which can be applied usingphotolithography methods known in the art. It allows electricalcomponents to be fabricated on and/or coupled to the top or bottomsurface or interior of the substrate. Multiple conductive portions canbe fabricated on the substrate to fabricate one or more electroniccomponents such as capacitors, resistors and inductors and circuitsusing these components. For example, two conductive portions can beplaced at a selectable distance across the thickness of the substrate toconstruct a capacitor, while a third conductive portion can be used toconstruct an inductor. Multiple components can be so fabricated toconstruct one or more of an LC, RC, or LRC circuit. Such circuits can becoupled to the connecting pins to provide a filtering function (e.g.,high pass, low pass, etc) or other function for each pin or a selectablegroup of pins. In this way, the space requirements within the housingcan be reduced because such circuits which would typically requiremultiple separate components can now be fabricated directly on thesubstrate with no separate connector. Also the components and circuitsfabricated on the substrate can form an integral part of circuitrywithin the implant housing. For example, one or more componentsfabricated on the substrate (e.g., capacitors, inductors, etc) can be anintegral part of a pacing, sensing, power or other circuit. Again, suchintegral configurations can achieve space and cost savings because theneed for multiple separate electrical components and associatedconnections is reduced.

In particular embodiments, the conductive portion can be used tofabricate an antenna on a top surface of the substrate. The antennacomprises a conductive trace fabricated on a top surface of thesubstrate. The antenna is configured to send and receive signals betweenthe medical implant when it is implanted in the body of a patient and acommunication device external to the patient's body such as a PDA,portable computer or other communication device. Use of such an integralantenna reduces the number of separate components for the implant andthe associated manufacturing cost. The antenna can be sized andotherwise configured to send and receive signals in a selectablefrequency range such as the 400 MHz to 6 GHz frequency range with aspecific embodiment of 402 to 405 MHz corresponding to the MICS standardestablished by the FCC. Other frequency ranges are also contemplatedcorresponding to one or more standards for medical electronics orrelated products. This can be achieved by fabricating the antenna tohave one or more turns and selection of the permittivity of thesubstrate which in specific embodiments, can be greater than 5, 10 or 30with high permittivity values achievable through use of a ceramicsubstrate such as alumina zirconia or combinations thereof. In variousembodiments, the conductive portion can also be configured to be used asan electrical connector to couple one or more separate components anddevices to the lid structure. Such components can include capacitors,inductors resistors, diodes etc, while the devices can includemicroprocessors, ASIC, DSPs and memory devices. In these and relatedembodiments, the conductive portion can be configured to have a patternor architecture for making specific connections to specific components(e.g., capacitors) and devices (e.g., microprocessors). One example ofsuch a connector architecture can comprise a pattern of tracesconfigured to align with the pins or connectors of a microprocessor orASIC. Other patterns can be employed for other devices. The pattern oftraces can be produced using photolithography or like methods.

Embodiments described herein provide a lid structure for a medicalimplant (MI) housing or container for MI devices such as cardiacpacemakers, defibrillators, gastric pacemakers, neural stimulators andother like devices. Referring now to FIGS. 1-3, preferred embodiments ofa lid structure 10 (also described herein as cap or cover structure 10)for use with a MI housing will typically include a monolithic substrate20 (also known as substrate 20), a frame 30, a plurality 41 of vias 40and pins or other connecting elements 50 (also referred to as connectors50) at least one of which extends through the vias. Substrate 20 whichwill typically comprise one or more dielectric materials known in theart, includes a conductive portion 70. Frame 30 can comprise titanium,steel or other metal and will typically be gold brazed to substrate 20,though other metallurgical joining techniques are also contemplated.Typically, frame 30 extends all the way around the perimeter 20P ofsubstrate 20, but it may, in some embodiments, extend only partwayaround perimeter 20P. Also as is described herein, frame 30 may extendbelow the bottom side of the antenna so as to have a lip or flange 30L.Frame 30 including lip 30L can be constructed by molding, machining,stamping or other metallurgical fabrication known in the art.

Substrate 20 includes an interior 20 i, a top surface 20 t positioned ona top side of 10 t of lid 10 and a bottom surface 10 b positioned on abottom side 10 b of the lid (for purposes of special reference, top andbottom surfaces 20 t and 20 b are also sometimes referred to herein astop and bottom sides 20 t and 20 b). Accordingly, in variousembodiments, conductive portion 70 can be positioned on the top orbottom substrate surface 20 t or 20 b or interior 20 i. Also, multipleconductive portions 70 can be fabricated at each of these locations toconstruct one or more electrical components as is described herein.

Substrate 20 can comprise one or more dielectric materials includingvarious dielectric ceramics known in the art. Also, the substratedesirably has a permittivity and size allowing embodiments of antenna 70a discussed herein to be sized to fit onto the substrate top surface tosend and receive signals in a selected frequency range such as the 402to 405 MHz frequency range. In various embodiments, the permittivity ofthe substrate 20 can be greater than 1, 5, 10 or 30. In specificembodiments, the permittivity can be in the range from 1-10, 10-20,20-30 and 30-50. This can be achieved through the selection of one ormore high permittivity ceramics such as alumina or zirconia or othermaterial known in the art. The permittivity of the substrate materialcan also be selected for sizing the antenna for communication in otherfrequency ranges such as 30 to 300 MHz, 300 MHz to 3 GHz, and 3 GHz to30 GH. Also in various embodiments described herein, substrate 20 cancomprise one or more optically transparent dielectric materials such asglass or glass like materials, so as to allow for an optical window forthe passage of various wavelengths of light through the substrate.

Vias 40 will typically be through vias going from top side 20 t of thesubstrate to the bottom side 20 b. However, blind vias and buried viasare also contemplated. The vias 40 can be produced by laser or otherdrilling method known in the art. Typically, vias 40 will include goldor other conductive metal plating and can include pads 41 on both sidesof the substrate. The number of vias 40 can be in the range of 4 to 30with specific embodiments 10, 12, 14, 16, 18 and 20. Other numbers ofvias are also contemplated. Vias 40 are desirably dimensioned to allowpins 50 to project through or into the via. Vias 40 can be coupled topins 50 by brazing, soldering or other joining method known in the artso as to hermetically seal the via with the pin in place. In otherembodiments, vias 40 can comprise a blind via going from substratesurface 20 t or 20 b into substrate interior 20 i to allow access to aconductive layer 70 positioned in the substrate interior. They can alsobe hidden vias to allow access between two or more conductive portions70 positioned within the substrate interior 20 i.

Typically, the conductive portion 70 will comprise one or moreconductive metals such as copper, gold, silver, platinum and alloysthereof. The use of conductive polymers and semi-conductive materials isalso contemplated. The conductive portion can also comprise a single ormultiple layers of conductive or semi-conductive material. Also multipleconductive portions 70 can be fabricated at multiple locations on orwithin substrate 20 to fabricate various electrical components andprovide conductive locations for attachment of electrical components anddevices.

In many embodiments, conductive portion 70 can comprise one or moreconductive traces 70 which can have a variety of shapes and patterns.Trace 70 t can be varied in thickness from the micron to the mm leveland can have a variety of shapes including linear, rectangular,U-shaped, circular or like shape. The trace can be printed on substrate20 or applied through various photolithographic techniques known in theart.

Portion 70 including traces 70 t can be shaped and otherwise configuredto fabricate one or more electrical components 75 discussed herein, aswell as serving as connecting locations or features 70 l for variousexternally attached electrical components and devices. In particularembodiments, connecting location 70 l can be configured to have anarchitecture or pattern for aligning to the connecting pins of amicroprocessor or other electronic device or component. In variousembodiments, conductive portion 70 including traces 70 t can befabricated at a selected location on or in substrate 20 using variousprinting, laser jet printing, or photo-lithography methods known in theart (e.g., via the use of masks and photoresist).

An exemplary embodiment of a method of fabrication of lid or otherstructure 10 including a monolithic substrate 20 will now be presented.This method including the order of operations is exemplary with othermethods and sequences equally applicable. First, vias 40 could bedrilled in the substrate using laser drilling or other drilling method.Then the conductive portions 70 comprising one or more components 75could be printed or otherwise fabricated on the top, bottom or othersurface of the substrate. Pins 50 could then be brazed or otherwiseattached to vias 40 and the entire substrate 20 could be brazed orotherwise attached to frame 30. Finally, components 75 or circuits 76could be attached to conductive portions on the bottom side 20 b of thesubstrate.

Various embodiments of lid structure 10 can be configured to be attachedto a number of medical implant housings and containers described hereinand known in the art including cardiac, gastric, brain and spinalimplants. For purposes of illustration, a discussion will now bepresented of the attachment of structure 10 to a cardiac pacemakerhousing 110 c. However, it should be appreciated that pacemaker housing110 c is exemplary and other medical implant housings having differentshapes and comprising different materials are equally applicable.Referring now to FIGS. 3a-3b , the typical pacemaker 100 p includes ahousing 110 which typically comprises a metal container known as a can110 c. Can 110 c contains various electronic components and circuitry130 such as sensing, pacing and power circuitry, as well as a battery orother stored power supply 136. Many pacemakers will also include aheader 120 which sits atop can 110 c and includes one or more connectors120 c for coupling to pacemaker leads 100 l that are positioned within achamber of the heart H such as the Atria A or ventricle V.

Referring now to FIGS. 4-6, in particular embodiments, lid structure 10is configured to be joined to a pacemaker can 110 c or other implanthousing 110 so as to form a completely enclosed container; however,non-enclosed embodiments are also contemplated. Also, the lid structure10 is desirably hermetically sealed to can 110 c so as to prevent theingress of both liquid water and water vapor which may damage electricalcomponents and circuitry of the pacemaker. This is achieved byhermetically sealing frame 30 to can 110 c. Since frame 30 and can 110 care typically made of a biologically inert metal such as titanium,hermetic sealing of these two components can be achieved by brazing orthrough the use of other metallurgical joining methods known in the art.In various embodiments, this can be facilitated by constructing theframe to have a lip or inner flange 30 L which fits into or over can 110c or other housing 110 as is shown in FIG. 4. FIG. 5a shows such a lidstructure 10 attached to the can. Other joining methods (e.g., adhesivebonding or RF and ultrasonic welding) are also contemplated where one orboth of the frame or housing are constructed from a polymer or othernon-metallic material.

Lid structure 10 can have variety of shapes, but will typically have athin oblong oval shape, other shapes are also contemplated. Typically,lid structure 10 will have a flat profile but it may also be curved. Thesize and shape of structure 10 are configured to be able to mate to aselected housing 100, while controlling the shape of the assembledhousing 100′ or otherwise not significantly increasing its form factorso that it can fit in a desired implant site. In various embodiments,the length 10L of the structure 10 can be in the range of 10 to 100 mmwith specific embodiments of 40 and 60 mm. The width low can be in therange of 5 to 40 mm with specific embodiments of 10 and 30 mm. Thethickness 10S can be in the range of 0.25 to 2 mm with specificembodiments of 0.5, 0.75, 1.25 and 1.5 mm.

In various embodiments, lid structure 10 can be configured to beattached in any number of orientations with respect to can 110 c orother housing 110. In the embodiment shown in FIG. 5a , lid structure 10can be positioned substantially parallel with respect to the horizontalaxis 110 ha of housing 110. In other embodiments shown in FIG. 5b , thelid structure can be positioned attached at a selectable angle 10 a withrespect of axis 110 ha. Angle 10 a can be in the range from 1 to 80°,with specific embodiments of 30, 45 and 60°. Use of an angled lidstructure including substrate 20 allows for substrate having largersurface area (with respect to top opening 110 t of the housing) whichallows for increased area for fabrication and attachment of componentsto the substrate. It also provides for additional space within thehousing for the components of the pacemaker 100 or other medicalimplant.

For many pacemakers, in addition to a can 110 c, the pacemaker alsoincludes a connector assembly known as a header 120 that typically sitsatop can 110 c and includes one or more connectors 120 c for connectingto a pacemaker lead 100 l. Accordingly, in addition to being configuredto be coupled to the pacemaker can 110 c, in various pacemakerapplications, lid structure 10 including pins 50 be configured to becoupled to the pacemaker header 120, as is shown in FIG. 6, or otherrelated connector structure which sits atop the pacemaker. Pins 50 aredesirably configured to engage or otherwise be coupled to one or morefemale connectors 120 fc in the header which are connected to thepacemaker leads 110 l. Alternatively, the pins can be directly coupledto the lead connectors.

Referring now to FIGS. 7a-7d , instead of forming part of a lidstructure that, is in turn, joined to housing 110, in some embodiments,the substrate can be directly and hermetically joined to the housing 110so that the substrate 20 is integral to the housing and forms part ofthe housing wall 110 w as shown in FIG. 7b . In these and relatedembodiments, the substrate can be hermetically joined to a frame 30which is then hermetically joined to a housing body 110 b whichcomprises the housing 110 with an opening 110 o that is shaped toreceive the frame or as is shown in FIG. 7a (alternatively, substrate 20can be directly joined to housing body 110 b). Also in variousembodiments, substrate 20 can be positioned at any number of locationson housing 110 including sides 110 s with housing body 110 b including aspace 110 o for the positioning of the substrate. Again, in suchembodiments, the substrate can include one or more attached components75 or circuits 76 allowing for modular assembly of any number ofcircuits and components of implant 100. Also, multiple monolithicsubstrates 20 can be positioned in multiple locations 100 l on housing110 including locations in a different spatial planes 110 p including atleast a first and second plane 110 p 1 and 110 p 2. Such locations 110 lcan include the top 110 t and sides 110 s of the housing as is shown inFIG. 7 c.

Embodiments having multiple substrates 20 allow for the positioning ofpins or other connecting elements 50 in multiple locations on thehousing. In use, such embodiments can facilitate connection of thehousing to one or more leads 100 l both in terms of manufacturabilityand reliability. For example, instead of having to direct all of theleads to one central connector location on the housing such as top 110t, the proximal end 100 lp of the lead (which is the end of the leadattached to can 10 c or other housing 110) can now be positioned at alocation on the housing which is closest to the distal end 110 ld of thelead or otherwise involves lesser amounts of bending of the lead. Thisreduces the length of the lead and also reduces various forces on thelead including one or more of the amount of tension, compression ortorsion the lead is subject to. This in turn, improves lead reliabilityby reducing the likelihood of the lead distal end from being dislodgedfrom the target site, (e.g., the atria), or disconnected from thepacemaker at the proximal lead end. It also reduces incidence ofshearing or other lead mechanical failure due to the reduced forceapplied on the lead.

In various embodiments of a medical housing 110 having multiplesubstrates 20, the substrates may of a specific type or section 25including a selected set of components such as connector elements 50,electrical components 75 or architecture 78 (discussed herein) for aparticular location. For example, one embodiment of substrate type 25shown in FIG. 7d may include a connector substrate 25 c that includesselected number of connector elements 50 (along with conductive tracesto one or more elements 50) so as to make a connection to housing 110 ata selection location 110 l. Multiple connector substrate sections 25 ccan be positioned in proximity or in different locations on the housingto produce a selected configuration of connector elements 50 (e.g., twoside by side sets of 4 pins). In use, such embodiments facilitatecustomized fabrication of housing 110 by allowing placement ofconnective elements 50 at selected locations on the housing using offthe shelf substrate sections.

Another embodiment of a particular substrate type 25, can include abattery substrate 25 b, in which substrate 20 includes a battery orother power supply 79 positioned on a bottom surface 20 b of thesubstrate as is shown in FIG. 7e . Similar to the preceding embodiment,this embodiment allows the positioning of a battery 79 or multiplebatteries 79 at any number of locations on the housing. Further, suchembodiments allow for the positioning of battery(ies) 79 at locationswithin the housing which allow for improved packing efficiency withinthe housing, e.g., the shape of the battery correlates to the shape ofthe space, and/or the battery can be positioned in open space locationsin the housing which were previously inaccessible without the use of thesubstrate section 25 b.

In particular embodiments, all or a portion of substrate 20 can befabricated from optically transparent materials such as glass, quartz ora transparent biocompatible polymer known in the art so as to comprisean optical window 21 that allows for transmission of light throughwindow 21 as is shown FIG. 7f . Window 21 can be configured for avariety of uses including sensing and optical communication. In sensingapplications, the window can configured to allow for optical sensing ofvarious physiological parameters, such as blood glucose, blood oxygensaturation, etc. This can be achieved through the use of an opticaldevice 90 including emitter 90 e such as a diode and a detector 90 dsuch as a photomultiplier as is shown in FIG. 7g . Emitter and detector90 e and 90 d can be configured for the emission and detection of awavelength for detection of a desired physiological analyte 91 (e.g.,blood glucose) or detection of a particular cell type 92 or an amount ofthrombus, collagen or other bio-layer attached to the housing.

In another embodiment shown in FIG. 7h , window 21 can configured as anoptical coupling 22 for sending and receiving and receiving opticalsignals 23 between the housing interior 100 i and the housing exterior100 e. This can be achieved through the use of a fiber optic or otheroptical conduit 94 positioned beneath the window which leads to anoptical switch or communication device 95 or an optical detector 90 dand emitter 90 e positioned beneath the window.

In particular embodiments where the implant is positioned transdermally,optical communication with implant 100 can be achieved through the useof infrared or other wavelengths of light that are transmitted throughthe skin. In such applications, an external fiber optic or other opticalcommunication device is positioned adjacent or in close proximity to thelayer of skin overlying the optical 21 window of the implant housing.

Embodiments of optical window 21 can be employed as an optical coupling22 to allow for one or more of the following functions: i) communicationof data from the pacemaker to an external monitoring device; ii)communication of programming from an external computer to allow forreprogramming of the pacemaker software stored in logic or memoryresources; iii) optical sensing of various physiological data by sensingthe site around the implant; and iv) transmission of an opticalstimulating or pacing signal to surrounding or other tissue. Externaloptical communication can be achieved through use of fiber optic devicessuch as a fiber optical catheter or like device that is positionedwithin proximity of the implant site.

Referring now to FIG. 7i , in various sensing applications using window21, physiological data that are sensed through optical window 21 can beused as an input 26 to modulate or otherwise control pacing signals 100s sent out by pacemaker or other device 100. Input 26 can be used tosupplement electrical inputs 27 received from pacing leads 100 l tocontrol pacing signals 100 s or it can be the primary or stand aloneinput. Suitable inputs 26 can include sensed data of blood pressure,pulse rate, EKG, peristaltic wave rate, respiration rate, various bloodgases including blood oxygen saturation and CO₂ levels. In use, input 26provides an additional signal that can be used to fine tune or otherwiseadjust pacing signals 100 s generated by the pacemaker. For example,sensed data on blood pressure or pulse rate can be used to adjust therate of pacing signal 100 s. In some cases, input 26 can actually beused as an override or primary signal such as when pulse rate or bloodpressure have fallen below a particular threshold.

In various stimulating or pacing applications using window 21, anoptical signal 28 can be sent from the window to provide stimulation toone or more tissue sites T such as the brain, optic nerve, eye, ganglia,spine or other like site. Signals 28 can be used to treat a variety ofneurological disease and conditions including epilepsy, migraineheadaches and chronic pain. In particular applications, optical signals28 can be used to treat, inhibit or prevent epileptic or otherneurological seizures by providing an optical input to a foci orsurrounding tissue in the brain causing the seizure. Optical signals 28can also be used in combination with one or more electrical signals 29which are delivered to tissue site T to treat one or more neurologicalor other conditions (e.g., cardiovascular, GI, etc.). The electricalsignals 29 can be generated by device 100 or a separate device. They canalso be synchronized with optical signals 28. Optical signals 28 canalso be configured for pacing and can be sent to provide pacing of oneor more tissue sites including the heart, stomach, intestine and othersites.

In one or more embodiments including an optical window 21, the windowcan include a coating or layer 24 configured to minimize the attachmentof cells and proteins to the window so as to maintain the opticaltransparency of window 21 for long term periods of implantation. Coatingor layer 24 can comprise low surface tension polymers such as PTFE,silicones and polyurethane formulated to be optically transparent ortranslucent and/or one or more eluting compounds used to maintain thepatentcy of cardiovascular stents. Such compounds can include one ormore of anti-neoplastics such as PACLITAXEL, immunosuppressives such asSIROLIMUS and healing factors such as VGEF. Drug eluting embodiments ofcoating 24 can be configured to elute drug for selectable periods offive to ten years or longer so as to maintain the optical transparencyof window 21. Coating 24 can also be applied to nontransparentembodiments of substrate 20 so as to improve the biocompatibility of thesubstrate, in these embodiments coating 24 does not necessarily have tobe transparent.

As is described above, conductive portions 70 can be used to fabricate anumber of electrical components 75 on or within substrate 20. Referringnow to FIGS. 8-10, in various embodiments these components can includecapacitors 75 c, resistors 75 r, inductors 75 i and antennas 75 a.Capacitors 75 c can be fabricated by placement of a first and secondconductive portion 70′ and 70″ at a selectable distance 20 d along thethickness 20 w of the substrate 20 to produce a selectable amount ofcapacitance. In various embodiments, capacitor 75 c can be fabricated bypositioning portions 70′ and 70″ on the top and bottom surfaces 20 t and20 b of the substrate (FIG. 9a ), within the interior 20 i of thesubstrate (FIG. 9b ), or by positioning one conductive portion can beplaced on the surface and another within interior 20 i (FIG. 9c ).

Inductors 75 i can be fabricated using a conductive trace 75 t having aspiral pattern. Resistors 75 r can be fabricated by narrowing thethickness of conductive trace or use of resistant materials in thetrace. Multiple components 75 can be fabricated on the substrate toconstruct one or more circuits 76, such an LC, RC, or LRC circuit. Invarious embodiments, circuits 76 can be coupled to the connecting pins50 to provide a filtering function (e.g., high pass, low pass, etc.) orother function for each pin or a selectable group of pins. In this way,the space requirements within housing 110 can be reduced in thatcircuits which would typically require multiple separate components cannow be fabricated directly on the substrate 20.

In various embodiments, substrate 20 can comprise a multilayer substrate20 ml with fabricated conductive portions 75 arranged to make or morecomponents 75 on each layer 20. FIGS. 10a-10e show aspects of suchembodiments. FIG. 10a illustrates a top layer 20 t 1, including anantenna 75 a. FIG. 10b illustrates an interior layer 20 i 1 having afirst capacitor plate 75 c 1. FIG. 10c illustrates another interiorlayer 20 i 1′ having a second capacitor plate 75 c 2 so as to comprise acapacitor 75 c. FIG. 10d illustrates a bottom layer 20 b 1 including aconnector architecture 78 for an attached component 75 or device 77.FIG. 10e shows the entire multilayer substrate 20 ml along with attachedcomponents 75 and devices 77. Use of a multilayer substrate 20 mprovides for additional space savings since multiple components 75 whichotherwise occupy space in housing 110 can now be positioned in thesubstrate 20 which comprises a wall 110 w of housing 110.

The individual layers 20 of multilayer substrate 20 ml can bemechanically connected by use of inserted pins 50 projecting throughvias 40. Pins 50 can also be used to make the electrical connectionbetween components 75 on each substrate layer 20. In use, embodiments ofmultilayer substrate 20 ml allow for the additional savings of spacewithin housing 110 since there are additional substrate layers 20 forfabrication of components 75 which would otherwise take up space in thehousing. Also, multiple electrical components 75 and circuits 76 can becoupled via means of conductive portions 70 and/or pins 50 ratherbulkier wires. Further space saving can be achieved by the fact thatcomponents 75 can be placed in very close proximity either on the samesubstrate layer 20 or different substrate layers 20′ of a multilayersubstrate 20 ml. This too eliminates the need for wires and/or the needfor other forms of bulky or lengthy electrical connection.

As describe above, in various embodiments, substrate 20 or multilayersubstrate 20 ml can be configured to provide a connector architecture 78used to electrically connect various components 75 and devices 77 tosubstrate 20 or a multilayer substrate 20 ml. Architecture 78 can beconfigured for electrical connection to specific electronic devices suchas microprocessors, memory devices (e.g., ROM, RAM, DRAM, etc.), DSP's,AD converters and like devices. This can be achieved by configuring oneor more connecting points 78 p in the architecture 78 to align withcorresponding connecting points on devices 77 so that device 77 alignswith architecture 78. Connecting points 78 p may also align with one ormore vias 40 to allow for connection to pins 50 and thus a connection toelectrical components and leads outside housing 50. In use, architecture78 allows for spacing savings in several respects. First, it caneliminate the need for an external connector (external in this casemeans external to the connected device, not necessarily external to thehousing), such as a flexible connector, that some pace makers employ tomake connections between electrical devices and components inside thepacemaker housing and components and leads outside the housing. Alsoarchitecture 78 allows components 75 and devices 77 to be placed inmultiple spatial orientations (e.g., in multiple planes) so as tooptimize the use of space within the housing 110. For example,architecture 78 may allow the use of a device 77 to be placed invertical orientation which would not otherwise fit in a horizontalorientation due to the narrow thickness of some pacemaker housings. Theymay also allow connected components to be placed in different spatialorientations from other devices comprising the circuitry 130 ofpacemaker 100 p. Additionally, they can allow the use of previouslyunusable space by being able to connect components directly to the walls110 w of housing 110.

Referring now to FIG. 11a , some of the typical circuitry 130 andelectronic devices 140 in a pacemaker 100 p or like device can includepower control circuitry 131, amplification and sensing circuitry 132,pacing circuitry 133, telemetry circuitry 134,micro-controller/micro-processor devices 141 and memory devices 142. Invarious embodiments, one or more of the components 75 and circuits 76fabricated on the substrate 20 can form an integral part of these orcircuitry of components of pacemaker 100. Referring now to FIG. 11b , inone embodiment, one or more of an antenna 75 a, inductor 75 i,capacitor, 75 c that are fabricated on substrate 20 can be an integralpart of into a telemetry circuit 134 of pacemaker 100 p or other medicalimplant. In use, such integral configurations can achieve space and costsavings because the need for multiple separate electrical components andassociated connections is reduced.

Referring now to FIGS. 1, 10 a and 12, in many embodiments, substrate 20can include an antenna 75 a desirably fabricated on substrate top side20 t so as to send and receive signals 80 to and from an externalcommunication device 200 when the pacemaker is implanted in the body.Antenna 75 a will typically comprise at least one conductive trace 70 tthat is sized and otherwise configured to send and receive signals in aselectable frequency range such as the 400 MHz to 6 GHz frequency rangewith a specific embodiment of 402 to 405 MHz corresponding to the MICSstandard established by the FCC. Other frequency ranges are alsocontemplated corresponding to one or more standards for medicalelectronics or related products such as those corresponding to theMedical Data Service (MDS), Wireless Medical Telemetry (WMT) andIndustrial, Scientific & Medical (ISM) standards. This can be achievedby fabricating the antenna to have one or more turns and selection ofthe permittivity of the substrate material as is discussed herein. Thetrace 70 t for antenna 75 a can have a have a variety of shapesincluding linear, rectangular, U-shaped, circular or like shape and caninclude one or more turns so as to form a series of inward concentricshapes. The length and width of structure 10 can be sized to allow forthe selected size and shape of selected antenna 70 while still allowingdistance between the antenna and the perimeter 10P of structure 10.

The shape and other properties of antenna 70 a (e.g., impedance, etc)are configured to be able to send and receive signals 80 between theimplant and a external communication device 200 positioned several ormore feet away. In many embodiments, this can be achieved by configuringthe antenna to send and receive signals in the MICS frequency range(about 402 to 405) which allows for communication at distances of about2 meters or so. In various embodiments communication device 200 cancomprise a PDA, computer or other RF based communication device. Thesignals 80 which are sent and received can be used to send data frompacemaker or other device 100, perform various diagnostic test on thepacemaker and reprogram the pacemaker.

CONCLUSION

The foregoing description of various embodiments of the invention hasbeen presented for purposes of illustration and description. It is notintended to limit the invention to the precise forms disclosed. Manymodifications, variations and refinements will be apparent topractitioners skilled in the art. For example, embodiments of the lidstructure have broad application to a number of implanted medicalproducts including implantable pulse generators, pace makers,cardioverter-defibrillators and other cardiac devices, gastricpacemakers and other gastric stimulators, spinal pain relief and otherspinal stimulators, implanted neural stimulators for Parkinson's diseaseand other neural and muscle stimulators and cochlear implants

Elements, characteristics, or acts from one embodiment can be readilyrecombined or substituted with one or more elements, characteristics oracts from other embodiments to form numerous additional embodimentswithin the scope of the invention. Moreover, elements that are shown ordescribed as being combined with other elements, can, in variousembodiments, exist as standalone elements. Hence, the scope of thepresent invention is not limited to the specifics of the describedembodiments, but is instead limited solely by the appended claims.

What is claimed is:
 1. A method for stimulating neural tissue to treat aneurological condition, the method comprising: providing a stimulatorapparatus configured to operate in or on the neural tissue, thestimulator apparatus including a substrate comprising a transparentdielectric material and including an optical window coated on anexterior portion by a transparent polymeric layer comprising a compoundconfigured to minimize attachment of cells to the optical window so asto maintain an optical transparency of the optical window for anextended period of time, the stimulator apparatus configured to generateone or more optical stimulation signals; and delivering an opticalstimulation signal generated by the stimulator apparatus to the neuraltissue through the optical window to treat the neurological condition.2. The method of claim 1, wherein the compound comprises an elutingcompound configured to minimize attachment of cells to the opticalwindow, the method further comprising: eluting the compound from thecoating for an extended period of time so as to maintain opticaltransparency of the optical window.
 3. The method of claim 2, whereinthe compound is eluted from the coating for a period up to ten years soto maintain the transparency of the optical window.
 4. The method ofclaim 1, wherein the optical stimulation signal is delivered to braintissue to treat the neurological condition.
 5. The method of claim 1,wherein at least a portion of the stimulator apparatus is implanted inthe skull.
 6. The method of claim 1, wherein at least a portion of thestimulator apparatus is implanted in the brain.
 7. The method of claim6, wherein the optical stimulation signal is further delivered to allowfor measurement of changes in optical properties of the brain tissue. 8.The method of claim 1, wherein the optical stimulation signal isconfigured to treat an epileptic seizure.
 9. The method of claim 8,wherein the optical stimulation signal is configured to inhibit orprevent the epileptic seizure.
 10. The method of claim 8, wherein theoptical stimulation signal is delivered to a foci in the brain causingthe epileptic seizure.
 11. The method of claim 10, wherein the opticalstimulation signal is delivered to tissue surrounding a foci in thebrain causing the epileptic seizure.
 12. The method of claim 1, furthercomprising: delivering an electrical stimulation signal to brain tissueto treat the neurological condition.
 13. The method of claim 12, whereinthe electrical stimulation signal is generated by the stimulator. 14.The method of claim 12, wherein the electrical stimulation signal issynchronized with the optical stimulation signal.
 15. The method ofclaim 12, wherein the electrical stimulation signal and the opticalstimulation signal produce an aggregate effect in the neural tissue totreat the neurological condition.
 16. The method of claim 1, wherein theoptical stimulation signal is configured to treat a migraine headache.17. The method of claim 1, wherein the optical stimulation signal isconfigured to treat chronic neurological pain.
 18. The method of claim1, wherein the optical window is coupled to an optical conduit, themethod further comprising: delivering the optical stimulation signal tothe neural tissue through the optical conduit.
 19. The method of claim18, wherein at least a portion of the optical conduit is implanted inthe neural tissue.
 20. The method of claim 18, wherein the opticalconduit comprises an optical fiber.
 21. The method of claim 7, furthercomprising: measuring the optical properties of the brain tissue throughthe optical window, the optical properties including one or more of ablood glucose level or a blood oxygen saturation.
 22. The method ofclaim 21, further comprising: modulating the optical stimulation signalin response to the measured optical properties of the brain tissueexceeding or dropping below a predetermined threshold.
 23. The method ofclaim 1, wherein the substrate is positioned near a wall of the housing.24. The method of claim 23, wherein the substrate abuts a wall of thehousing.